I get smoke and cigarette butts all times to my apartment and help is good news. – Russel, VIC
The first step is to identify the unit from where the cigarette butts are coming and talk to your neighbours about the problem.
If the issue continues thereafter, you can contact your owners corporation manager and they can in turn contact the owners with formal letters or a notice of breach since their activities are interfering with your right to enjoy your property as per your building rules.
Here is an interesting article about why building rules should not be breached in owners corporations.